نشریه علوم به زراعی گیاهی
سال ششم شماره 2 (پاییز و زمستان 1395)

The recent research was carried out in order to evaluate effects of salt stress on growth and some physiological traits of four spring canola cultivars (Brassica napus L). canola cultivars were Hyola401, Hyola308, Hyola60 and RGS003 and salt stress treatments were applied using salt solutions with EC values of 0 (control), 4, 8 and 12 dsm-1. The experiment was conducted as factorial in basis RCBD with three replications in Dezful research station in Safi Abad, 2010-2011. The results showed that salt stress caused significant decrease in photosynthesis, chlorophyll content, dry matter weight per plant and grain yield per plant. Salt stress effects on traits such as stomatal conductance and relative water content of leaf that caused decrease in photosynthesis and dry matter weight per plant, plant height, grain weight per plant and grain yield in plant. The study showed that the use of some traits such as photosynthesis rate and chlorophyll content that have positive correlation with dry matter weight per plant and grain yield per plant may have been suggested as an important selection criterion for salt-tolerance in brassica.

Estimation of genetic diversity, combining ability and heterosis of maize inbred lines for breeding aims are very important and would determine breeding strategies. In order[dfp1] to estimate potential genetic Iranian corn inbred lines using diallel and AMMI methods, fourteen corn inbred lines cross were studied according to diallel scheme. Parents and their hybrids were evaluated in 2007 at Seed and Plant Improvement Institute, Karaj, using Randomized Complete Block design with three replications. Results indicated that Significant differences (p<0.01) were observed among the genotypes for all studied traits, therefore Griffing’s method 2, model 1 was chosen for subsequent diallel analysis. Variances due to GCA and SCA were significant for all studied traits (P < 0.01). Results indicated that for number of kernel row per ear, 100 seed weight, cob percent and kernel moisture percent additive gene effects were more important than the non additive ones, but for grain yield, plant height, ear height, ear diameter, number of kernel per row and number of kernel per ear non additive gene effects were more important than the additive ones. For ear length and kernel weight per ear, importance of additive and non additive gene effects was the same. The best AMMI model for yield was AMMI3 explained 75.6% of interaction variance. The best general combinatory for yield were K166B, K3615/2 and K3653 lines. The highest specific combining ability and mid-parent heterosis for yield according to Griffing, first and second AMMI components, was observed in MO17 × K3653, K166B × K3653, K166B × K3653, A679 × K3544/1 and K3653 × K3493/1.

In order to evaluation of grain yield changes and some physiological triats in bread wheat genotypes under drought stress during garin filling period, this study was conducted with 23 bread wheat lines and cultivars including twenty drought resistant and three susceptible lines in split plot design with three replications. Main and sub plots were allocated to irrigation and wheat cultivars/lines, respectively. Irrigation treatments were including full irrigation and drought stress during flowering stage. The results showed that the effects of irrigation regimes on thousand kernel weight and number of spike per square meter were statistically significant at 1% and 5% levels respectively. The seed weight and the number of spike per square meter was more important in grain yield in both irrigation regimes. The maximum thousand grain weight by 38.7 g recorded in SD-86-14 and SD-86-3 most spike m2 obtaind by 1087 in Chamran variety and the best result for grain yield considered in SD-86-11 by 7170 kg/ha.

In order to investigate the effects of grain growth characteristic and yield components on grain yield of wheat cultivars, an experiment was carried out in randomized complete block design with three replications at Golestan province in 2008-2009. Experimental cultivars were Inia, Khazar 1, Golestan, Tajan, Atrak, Pastor, Darya, Zagros, Falat and Kohdasht. Pastor cultivar had maximum and Inia cultivar had minimum numbers of grain per spike. The highest seed yield belonged to Golestan, Falat, Atrak, Pastor and Darya and the lowest seed yield were seen in Inia cultivars. The highest and lowest grain harvest index was related to Falat Cultivar (46/8 percent) and Tajan cultivar (33/8percent) respectively. Filling grain period and grain number per spike had positive correlation with grain yield. Therefore, it seems that increasing sink strength by increasing the number of seed per spike and grain filling rate can lead to an increase in the yield of wheat cultivars.

In order to study the effect of oxyflorfen herbicide on Convolvus arvensis control in mung bean cultivation, an experiment was conducted  at Ahwaz region in 2011. Factorial experiment was done in completely randomized block design with four replication with two mung bean cultivars (Gohar and Parto) and weed control levels include three oxyflorfen herbicide dose (1, 1.5 and 2 L/ha) along with weed free and weedy as control. The reviewed agronomic traits were number of branches, plant height, number of pods, number of seeds per pods, weight of 100 seeds, seed yield and assessment criteria of weeds  including density, height, number of leaves and weed dry weight. Results showed significant differences in traits among treatments. Oxyflorfen herbicide with 2 L/ha showed the best performance among weed control treatments. The maximum seed yield was found in the highest level of oxyflorfen herbicide (1/5 t/ha). The comparison of partov cultivar and Gohar cultivars showed higher genetic characteristics of Parto cultivar.

In order to compare the effectiveness of new herbicide, nicosulfuron and foramsulfuron in compared to commonly used corn herbicides in Birjand, a study was conducted based on randomized complete block design with 12 treatments and three replications in 2009 in Birjand University Agricultural Research Field. Treatments were post emergence application of nicosulfuron and foramsulfuron in amounts of 1, 1.5, 2 and 2.5 L/h, post emergence application of 2, 4 –D + MCPA at 1.5 L/ha concentration and pre emergence application of alacholor and atrazin at 5 L/ha and 1.5 kg/ha, respectively. Moreover, weed free and weedy check plots were considered in each block. The results showed that applying nicosulfuron (2 L/ha) reduced 68% of green foxtail density (Setaria viridis L.), while no significant difference was seen in applying foramsulfuron, nicosulfuron (2.5 L/ha) and alacholor. The use of nicosulfuron 2.5 L/ha reduced 87% of dry matter weight of green foxtail (Setaria viridis L.). However there were no significant difference between the treatment of foramsulfuron (2 and 2.5 L/ha) and nicosulfuron (2 L/ha). Similarly, nicosulfuron and foramsulfuron (2.5 L/ha) decreased 88 and 81% of broad-leaved weeds density. The highest corn forage yield showed in foramsulfuron (2 and 2.5 L/ha) and nicosulfuron (2 and 2,5 L/ha) application

In order to study agronomic traits on sowing date and plant density of canola cultivars (B. napus L.), field experiments were carried out in Gorgan Agriculture experimental Station during 2002-2003 and 2003- 2004 cropping seasons. The experimental design was spilt plot factorial in a randomized complete block design with four replications. Four sowing date (Oct. 15th, Oct. 30th, Nov. 15th and Nov. 30th) were assigned to main plots and combination of canola cultivars (Hayola420 and R.G.S003) and plant densities (Including 80 and 120 plants/m2) were randomized to subplots. Late sowing date had negative effect on canola yield and yield components were the number of pod per plant, grain per pod, 1000 seed weight and seed oil content were reduced. Canola density have significant effect on seed yield and the highest canola seed yield was obtained at 80 plant/m2 (3012 kg/ha). The agronomic traits of sowing date and plant density only affected seed yield where the highest seed yield belonged to 15 Oct, 30 Oct and 15 Nov sowing date and 80 plants/m2 density and 30 Nov. sowing date with 120 plants/m2 density.